This invention relates to an annular butterfly valve body completely coated with a single elastomeric material.
Butterfly valves are known whose bodies are coated with elastomers, but in general the elastomers coating the interior and exterior of the body are of different hardnesses or of distinct characteristics. Moreover, the attaching of the elastomer coating onto the body is carried out either by means of anchor holes traversing the valve body or by gluing, the latter necessitating a thorough preparation of the surface of the body and limiting the choice of the elastomers used. Further, the passages for the shafts or axles of the butterfly through the body are not coated with elastomer, and therefore have to be precisely machined to allow the accurate placing of sealing gaskets and bearings.